Release v0.9.3

Changed

• Get python3 path by FindPython3 for multi platforms
• Support pico-sdk 2.1.1

Added

• Support Raspberry Pi Pico 2 series board (up to 96.0 KHz)
• Add GitHub Actions for build and release

Fixed

• Rescue mulfunction for __builtin_clz optimization for -O2, -O3 case (contributed by ldursw)